CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to and the benefit of Provisional Application No.
62/265,324 filed in the U.S. Patent and Trademark Office on December 9, 2015, and Non-Provisional
Application No.
15/185,315 filed in the U.S. Patent and Trademark Office on June 17, 2016.
TECHNICAL FIELD
[0002] Aspects of the present disclosure relate generally to wireless communication systems,
and more particularly, to the uplink channel structure for multiple access of users
with different modes in a time division duplex (TDD) subframe.
INTRODUCTION
[0003] Wireless communication networks, as for example described in 3GPP RWS-150012, 3GPP
R1-157082,
WO 2014/008106 A1,
WO 2013/060807 A1,
US 2013/301545 A1 are widely deployed to provide various communication services such as telephony,
video, data, messaging, broadcasts, and so on. Such networks, which are usually multiple
access networks, support communications for multiple users by sharing the available
network resources.
[0004] Within such wireless networks a variety of data services may be provided, including
voice, video, emails, and others. More recently, wireless communication networks are
being utilized for an even broader range of services, including mission critical applications
and remote control applications such as tele-surgery, where real-time feedback is
necessary. In such applications, very low latency is critical to enable a suitably
high quality of service. That is, the time for information to be transmitted from
a communication device, and a response received back at the communication device,
may need to be extremely rapid, on the order of milliseconds or less.
[0005] As the demand for mobile broadband access continues to increase, research and development
continue to advance wireless communication technologies not only to meet the growing
demand for mobile broadband access, but to advance and enhance the user experience.
BRIEF SUMMARY OF SOME EXAMPLES
[0006] The following presents a simplified summary of one or more aspects of the present
disclosure, in order to provide a basic understanding of such aspects. This summary
is not an extensive overview of all contemplated features of the disclosure, and is
intended neither to identify key or critical elements of all aspects of the disclosure
nor to delineate the scope of any or all aspects of the disclosure. Its sole purpose
is to present some concepts of one or more aspects of the disclosure in a simplified
form as a prelude to the more detailed description that is presented later.
[0007] Various aspects of the present disclosure provide for methods, apparatus, and computer
software for wireless communication utilizing a common uplink burst, wherein multiple
access for the common uplink burst is achieved for devices configured for a coupled
mode, and devices configured for a decoupled mode.
[0008] One aspect of the disclosure provides a method operable at a scheduling entity for
wireless communication over a time division duplex (TDD) carrier. According to the
method, a scheduling entity receives a first uplink burst from a coupled mode user
within each of a downlink-centric subframe and an uplink-centric subframe on the TDD
carrier, and the scheduling entity receives a second uplink burst, simultaneously
with the first uplink burst, from a decoupled mode user within each of the downlink-centric
subframe and the uplink-centric subframe on the TDD carrier. The first uplink burst
from the coupled mode user is combined with the second uplink burst from the decoupled
mode user on the TDD carrier utilizing non-orthogonal multiple access.
[0009] Another aspect of the disclosure provides a method operable at a scheduling entity
for wireless communication over a TDD carrier. According to the method, a scheduling
entity receives a first uplink burst from a coupled mode user within each of a downlink-centric
subframe and an uplink-centric subframe on the TDD carrier, and the scheduling entity
receives a second uplink burst, simultaneously with the first uplink burst, from a
decoupled mode user within each of the downlink-centric subframe and the uplink-centric
subframe on the TDD carrier. The first uplink burst from the coupled mode user is
combined with the second uplink burst from the decoupled mode user on the TDD carrier
utilizing orthogonal multiple access.
[0010] Another aspect of the disclosure provides a scheduling entity configured for wireless
communication over a TDD carrier. The scheduling entity includes a processor, a memory
communicatively coupled to the processor, and a transceiver communicatively coupled
to the processor. The processor and the memory are configured to receive a first uplink
burst from a coupled mode user within each of a downlink-centric subframe and an uplink-centric
subframe on the TDD carrier. The processor and the memory are further configured to
receive a second uplink burst, simultaneously with the first uplink burst, from a
decoupled mode user within each of the downlink-centric subframe and the uplink-centric
subframe on the TDD carrier. The first uplink burst from the coupled mode user is
combined with the second uplink burst from the decoupled mode user on the TDD carrier
utilizing non-orthogonal multiple access.
[0011] Another aspect of the disclosure provides a scheduling entity configured for wireless
communication over a TDD carrier. The scheduling entity includes a processor, a memory
communicatively coupled to the processor, and a transceiver communicatively coupled
to the processor. The processor and the memory are configured to receive a first uplink
burst from a coupled mode user within each of a downlink-centric subframe and an uplink-centric
subframe on the TDD carrier. The processor and the memory are further configured to
receive a second uplink burst, simultaneously with the first uplink burst, from a
decoupled mode user within each of the downlink-centric subframe and the uplink-centric
subframe on the TDD carrier. The first uplink burst from the coupled mode user is
combined with the second uplink burst from the decoupled mode user on the TDD carrier
utilizing orthogonal multiple access.
[0012] Another aspect of the disclosure provides a scheduling entity for wireless communication
over a TDD carrier. The scheduling entity includes means for receiving a first uplink
burst from a coupled mode user within each of a downlink-centric subframe and an uplink-centric
subframe on the TDD carrier. The scheduling entity further includes means for receiving
a second uplink burst, simultaneously with the first uplink burst, from a decoupled
mode user within each of the downlink-centric subframe and the uplink-centric subframe
on the TDD carrier. The first uplink burst from the coupled mode user is combined
with the second uplink burst from the decoupled mode user on the TDD carrier utilizing
non-orthogonal multiple access.
[0013] Another aspect of the disclosure provides a scheduling entity for wireless communication
over a TDD carrier. The scheduling entity includes means for receiving a first uplink
burst from a coupled mode user within each of a downlink-centric subframe and an uplink-centric
subframe on the TDD carrier. The scheduling entity further includes means for receiving
a second uplink burst, simultaneously with the first uplink burst, from a decoupled
mode user within each of the downlink-centric subframe and the uplink-centric subframe
on the TDD carrier. The first uplink burst from the coupled mode user is combined
with the second uplink burst from the decoupled mode user on the TDD carrier utilizing
orthogonal multiple access.
[0014] Another aspect of the disclosure provides a computer-readable storage medium including
code executable by a scheduling entity for wireless communication over a TDD carrier.
The code includes receiving a first uplink burst from a coupled mode user within each
of a downlink-centric subframe and an uplink-centric subframe on the TDD carrier.
The code further includes receiving a second uplink burst, simultaneously with the
first uplink burst, from a decoupled mode user within each of the downlink-centric
subframe and the uplink-centric subframe on the TDD carrier. The first uplink burst
from the coupled mode user is combined with the second uplink burst from the decoupled
mode user on the TDD carrier utilizing non-orthogonal multiple access.
[0015] Another aspect of the disclosure provides a computer-readable storage medium including
code executable by a scheduling entity for wireless communication over a TDD carrier.
The code includes receiving a first uplink burst from a coupled mode user within each
of a downlink-centric subframe and an uplink-centric subframe on the TDD carrier.
The code further includes receiving a second uplink burst, simultaneously with the
first uplink burst, from a decoupled mode user within each of the downlink-centric
subframe and the uplink-centric subframe on the TDD carrier. The first uplink burst
from the coupled mode user is combined with the second uplink burst from the decoupled
mode user on the TDD carrier utilizing orthogonal multiple access.
[0016] Another aspect of the disclosure provides a method operable at a coupled mode subordinate
entity for wireless communication over a TDD carrier. According to the method, a coupled
mode subordinate entity prepares a first uplink burst including a sounding reference
signal (SRS) in a first symbol and control information in a second symbol configured
to be demodulated based on the SRS. The coupled mode subordinate entity transmits
the first uplink burst within a subframe on the TDD carrier. The first uplink burst
is combined with a second uplink burst transmitted, simultaneously with the first
uplink burst, from a decoupled mode subordinate entity on the TDD carrier utilizing
non-orthogonal multiple access.
[0017] Another aspect of the disclosure provides a method operable at a coupled mode subordinate
entity for wireless communication over a TDD carrier. According to the method, a coupled
mode subordinate entity prepares a first uplink burst including a sounding reference
signal (SRS) in a first symbol and control information in a second symbol configured
to be demodulated based on the SRS. The coupled mode subordinate entity transmits
the first uplink burst within a subframe on the TDD carrier. The first uplink burst
is combined with a second uplink burst transmitted, simultaneously with the first
uplink burst, from a decoupled mode subordinate entity on the TDD carrier utilizing
orthogonal multiple access.
[0018] Another aspect of the disclosure provides a method operable at a decoupled mode subordinate
entity for wireless communication over a TDD carrier. According to the method, a decoupled
mode subordinate entity prepares a first uplink burst including a sounding reference
signal (SRS) in a first symbol and a demodulation reference signal (DM-RS) in a second
symbol decoupled from the SRS. The decoupled mode subordinate entity transmits the
first uplink burst within a subframe on the TDD carrier. The first uplink burst is
combined with a second uplink burst transmitted, simultaneously with the first uplink
burst, from a coupled mode subordinate entity on the TDD carrier utilizing non-orthogonal
multiple access.
[0019] Another aspect of the disclosure provides a method operable at a decoupled mode subordinate
entity for wireless communication over a TDD carrier. According to the method, a decoupled
mode subordinate entity prepares a first uplink burst including a sounding reference
signal (SRS) in a first symbol and a demodulation reference signal (DM-RS) in a second
symbol decoupled from the SRS. The decoupled mode subordinate entity transmits the
first uplink burst within a subframe on the TDD carrier. The first uplink burst is
combined with a second uplink burst transmitted, simultaneously with the first uplink
burst, from a coupled mode subordinate entity on the TDD carrier utilizing orthogonal
multiple access.
[0020] These and other aspects of the invention will become more fully understood upon a
review of the detailed description, which follows. Other aspects, features, and embodiments
of the present invention will become apparent to those of ordinary skill in the art,
upon reviewing the following description of specific, exemplary embodiments of the
present invention in conjunction with the accompanying figures. While features of
the present invention may be discussed relative to certain embodiments and figures
below, all embodiments of the present invention can include one or more of the advantageous
features discussed herein. In other words, while one or more embodiments may be discussed
as having certain advantageous features, one or more of such features may also be
used in accordance with the various embodiments of the invention discussed herein.
In similar fashion, while exemplary embodiments may be discussed below as device,
system, or method embodiments it should be understood that such exemplary embodiments
can be implemented in various devices, systems, and methods. The invention is defined
in the appended claims. Any references to embodiments not falling under the scope
of the claims must be understood as examples useful for understanding the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021]
FIG. 1 is a schematic diagram of a wireless communication network according to some
embodiments of the present disclosure.
FIG. 2 is a schematic block diagram illustrating a scheduling entity in communication
with a plurality of subordinate entities according to some embodiments of the present
disclosure.
FIG. 3 is a block diagram illustrating an example of a wireless communication device
according to some embodiments of the present disclosure.
FIG. 4 is a block diagram illustrating further detail of a scheduling entity in communication
with a subordinate entity according to some embodiments of the present disclosure.
FIG. 5 is a schematic diagram illustrating a downlink-centric subframe and an uplink-centric
subframe each including a common uplink burst according to some embodiments of the
present disclosure.
FIG. 6 is a schematic diagram showing a first common uplink burst configured according
to a coupled mode and a second common uplink burst configured according to a decoupled
mode.
FIG. 7 is a schematic diagram illustrating non-orthogonal multiple access in a common
uplink (UL) burst for coupled mode users and decoupled mode users according to some
embodiments of the present disclosure.
FIG. 8 is a schematic diagram illustrating orthogonal multiple access in a common
UL burst for coupled mode users and decoupled mode users according to some embodiments
of the present disclosure.
FIG. 9 is a schematic diagram illustrating a resource block having M contiguous tones
for transmission of a common UL burst according to an embodiment of the present disclosure.
FIG. 10 is a flowchart illustrating a non-orthogonal multiple access method for coupled
mode and decoupled mode users in wireless communication according to an embodiment
of the disclosure.
FIG. 11 is a flowchart illustrating an interference cancellation method for handling
interference between non-orthogonal uplink bursts of coupled mode users and decoupled
mode users according to an embodiment of the disclosure.
FIG. 12 is a flowchart illustrating a rise of thermal (RoT) based interference handling
method for handling interference between non-orthogonal uplink bursts of coupled mode
users and decoupled mode users according to an embodiment of the disclosure.
FIG. 13 is a flowchart illustrating an orthogonal multiple access method for coupled
mode and decoupled mode users in wireless communication according to an embodiment
of the disclosure.
FIG. 14 a flowchart illustrating a non-orthogonal multiple access method operable
at a coupled mode subordinate entity for wireless communication over a time division
duplex (TDD) carrier in accordance with an aspect of the disclosure
FIG. 15 is a flowchart illustrating an orthogonal multiple access method operable
at a coupled mode subordinate entity for wireless communication over a TDD carrier
in accordance with an aspect of the disclosure.
FIG. 16 is a flowchart illustrating a non-orthogonal multiple access method operable
at a decoupled mode subordinate entity for wireless communication over a TDD carrier
in accordance with an aspect of the disclosure.
FIG. 17 is a flowchart illustrating an orthogonal multiple access method operable
at a decoupled mode subordinate entity for wireless communication over a TDD carrier
in accordance with an aspect of the disclosure.
DETAILED DESCRIPTION
[0022] The detailed description set forth below in connection with the appended drawings
is intended as a description of various configurations and is not intended to represent
the only configurations in which the concepts described herein may be practiced. The
detailed description includes specific details for the purpose of providing a thorough
understanding of various concepts. However, it will be apparent to those skilled in
the art that these concepts may be practiced without these specific details. In some
instances, well known structures and components are shown in block diagram form in
order to avoid obscuring such concepts.
[0023] FIG. 1, two high-power base stations 110 and 112 are shown in cells 102 and 104;
and a third high-power base station 114 is shown controlling a remote radio head (RRH)
116 in cell 106. In this example, the cells 102, 104, and 106 may be referred to as
macrocells, as the high-power base stations 110, 112, and 114 support cells having
a large size. Further, a low-power base station 118 is shown in the small cell 108
(e.g., a microcell, picocell, femtocell, home base station, home Node B, home eNode
B, etc.) which may overlap with one or more macrocells. In this example, the cell
108 may be referred to as a small cell, as the low-power base station 118 supports
a cell having a relatively small size. Cell sizing can be done according to system
design as well as component constraints. It is to be understood that the access network
100 may include any number of wireless base stations and cells. The base stations
110, 112, 114, 118 provide wireless access points to a core network for any number
of mobile apparatuses.
[0024] FIG. 1 further includes a quadcopter or drone 120, which may be configured to function
as a base station. That is, in some examples, a cell may not necessarily be stationary,
and the geographic area of the cell may move according to the location of a mobile
base station such as the quadcopter 120.
[0025] In some examples, the base stations may be interconnected to one another and/or to
one or more other base stations or network nodes (not shown) in the access network
100 through various types of backhaul interfaces such as a direct physical connection,
a virtual network, or the like using any suitable transport network.
[0026] The access network 100 is illustrated supporting wireless communication for multiple
mobile apparatuses. A mobile apparatus is commonly referred to as user equipment (UE)
in standards and specifications promulgated by the 3rd Generation Partnership Project
(3GPP), but may also be referred to by those skilled in the art as a mobile station
(MS), a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote
unit, a mobile device, a wireless device, a wireless communications device, a remote
device, a mobile subscriber station, an access terminal (AT), a mobile terminal, a
wireless terminal, a remote terminal, a handset, a terminal, a user agent, a mobile
client, a client, or some other suitable terminology.
[0027] Within the present document, a "mobile" apparatus need not necessarily have a capability
to move, and may be stationary. Some non-limiting examples of a mobile apparatus include
a mobile, a cellular (cell) phone, a smart phone, a session initiation protocol (SIP)
phone, a laptop, a personal computer (PC), a notebook, a netbook, a smartbook, a tablet,
and a personal digital assistant (PDA). A mobile apparatus may additionally be an
"Internet of things" (IoT) device such as an automotive or other transportation vehicle,
a satellite radio, a global positioning system (GPS) device, a logistics controller,
a drone, a multi-copter, a quad-copter, a smart energy or security device, a solar
panel or solar array, municipal lighting, water, or other infrastructure; industrial
automation and enterprise devices; consumer and wearable devices, such as eyewear,
a wearable camera, a smart watch, a health or fitness tracker, a digital audio player
(e.g., MP3 player), a camera, a game console, etc.; and digital home or smart home
devices such as a home audio, video, and multimedia device, an appliance, a sensor,
a vending machine, intelligent lighting, a home security system, a smart meter, etc.
[0028] Within the access network 100, the cells may include UEs that may be in communication
with one or more sectors of each cell. For example, UEs 122 and 124 may be in communication
with base station 110; UEs 126 and 128 may be in communication with base station 112;
UEs 130 and 132 may be in communication with base station 114 by way of RRH 116; UE
134 may be in communication with low-power base station 118; and UE 136 may be in
communication with mobile base station 120. Here, each base station 110, 112, 114,
118, and 120 may be configured to provide an access point to a core network (not shown)
for all the UEs in the respective cells.
[0029] In another example, the quadcopter 120 may be configured to function as a UE. For
example, the quadcopter 120 may operate within cell 102 by communicating with base
station 110.
[0030] The air interface in the access network 100 may utilize one or more multiplexing
and multiple access algorithms to enable simultaneous communication of the various
devices. For example, multiple access for uplink (UL) or reverse link transmissions
from UEs 122 and 124 to base station 110 may be provided utilizing time division multiple
access (TDMA), code division multiple access (CDMA), frequency division multiple access
(FDMA), orthogonal frequency division multiple access (OFDMA), or other suitable multiple
access schemes. Further, multiplexing downlink (DL) or forward link transmissions
from the base station 110 to UEs 122 and 124 may be provided utilizing time division
multiplexing (TDM), code division multiplexing (CDM), frequency division multiplexing
(FDM), orthogonal frequency division multiplexing (OFDM), or other suitable multiplexing
schemes.
[0031] Within the access network 100, during a call with a scheduling entity, or at any
other time, a UE may monitor various parameters of the signal from its serving cell
as well as various parameters of neighboring cells. Further, depending on the quality
of these parameters, the UE may maintain communication with one or more of the neighboring
cells. During this time, if the UE moves from one cell to another, or if signal quality
from a neighboring cell exceeds that from the serving cell for a given amount of time,
the UE may undertake a handoff or handover from the serving cell to the neighboring
(target) cell. For example, UE 124 may move from the geographic area corresponding
to its serving cell 102 to the geographic area corresponding to a neighbor cell 106.
When the signal strength or quality from the neighbor cell 106 exceeds that of its
serving cell 102 for a given amount of time, the UE 124 may transmit a reporting message
to its serving base station 110 indicating this condition. In response, the UE 124
may receive a handover command, and the UE may undergo a handover to the cell 106.
[0032] In some examples, access to the air interface may be scheduled, wherein a scheduling
entity (e.g., a base station) allocates resources for communication among some or
all devices and equipment within its service area or cell. Within the present disclosure,
as discussed further below, the scheduling entity may be responsible for scheduling,
assigning, reconfiguring, and releasing resources for one or more subordinate entities.
That is, for scheduled communication, subordinate entities utilize resources allocated
by the scheduling entity.
[0033] Base stations are not the only entities that may function as a scheduling entity.
That is, in some examples, a UE may function as a scheduling entity, scheduling resources
for one or more subordinate entities (e.g., one or more other UEs). For example, UE
138 is illustrated communicating with UEs 140 and 142. In this example, the UE 138
is functioning as a scheduling entity, and UEs 140 and 142 utilize resources scheduled
by the UE 138 for wireless communication. A UE may function as a scheduling entity
in a peer-to-peer (P2P) network, and/or in a mesh network. In a mesh network example,
UEs 140 and 142 may optionally communicate directly with one another in addition to
communicating with the scheduling entity (e.g., a UE 138).
[0034] Thus, in a wireless communication network with a scheduled access to time-frequency
resources and having a cellular configuration, a P2P configuration, and a mesh configuration,
a scheduling entity and one or more subordinate entities may communicate utilizing
the scheduled resources. Referring now to FIG. 2, a block diagram illustrates a scheduling
entity 202 and a plurality of subordinate entities 204. Here, the scheduling entity
202 may correspond to the base stations 110, 112, 114, and 118. In additional examples,
the scheduling entity 202 may correspond to the UE 138, the quadcopter 120, or any
other suitable node in the access network 100. Similarly, in various examples, the
subordinate entity 204 may correspond to the UE 122, 124, 126, 128, 130, 132, 134,
136, 138, 140, and 142, or any other suitable node in the access network 100.
[0035] As illustrated in FIG. 2, the scheduling entity 202 may broadcast data 206 to one
or more subordinate entities 204 (the data may be referred to as downlink data). In
accordance with certain aspects of the present disclosure, the term downlink may refer
to a point-to-multipoint transmission originating at the scheduling entity 202. Broadly,
the scheduling entity 202 is a node or device responsible for scheduling traffic in
a wireless communication network, including the downlink transmissions and, in some
examples, uplink data 210 from one or more subordinate entities to the scheduling
entity 202. Another way to describe the system may be to use the term broadcast channel
multiplexing. In accordance with aspects of the present disclosure, the term uplink
may refer to a point-to-point transmission originating at a subordinate entity 204.
Broadly, the subordinate entity 204 is a node or device that receives scheduling control
information, including but not limited to scheduling grants, synchronization or timing
information, or other control information from another entity in the wireless communication
network such as the scheduling entity 202.
[0036] The scheduling entity 202 may broadcast a control channel 208 to one or more subordinate
entities 204. Uplink data 210 and/or downlink data 206 may be transmitted using a
transmission time interval (TTI). Here, a TTI may correspond to an encapsulated set
or packet of information capable of being independently decoded. In various examples,
TTIs may correspond to frames, subframes, data blocks, time slots, or other suitable
groupings of bits for transmission.
[0037] Furthermore, the subordinate entities 204 may transmit uplink control information
212 to the scheduling entity 202. Uplink control information may include a variety
of packet types and categories, including pilots, reference signals, and information
configured to enable or assist in decoding uplink data transmissions. In some examples,
the control information 212 may include a scheduling request (SR), i.e., request for
the scheduling entity 202 to schedule uplink transmissions. Here, in response to the
SR transmitted on the control channel 212, the scheduling entity 202 may transmit
in the downlink control channel 208 information that may schedule the TTI for uplink
packets. In a further example, the uplink control channel 212 may include hybrid automatic
repeat request (HARQ) feedback transmissions, such as an acknowledgment (ACK) or negative
acknowledgment (NACK). HARQ is a technique well-known to those of ordinary skill in
the art, wherein packet transmissions may be checked at the receiving side for accuracy,
and if confirmed, an ACK may be transmitted, whereas if not confirmed, a NACK may
be transmitted. In response to a NACK, the transmitting device may send a HARQ retransmission,
which may implement chase combining, incremental redundancy, etc.
[0038] The channels illustrated in FIG. 2 are not necessarily all of the channels that may
be utilized between a scheduling entity 202 and subordinate entities 204, and those
of ordinary skill in the art will recognize that other channels may be utilized in
addition to those illustrated, such as other data, control, and feedback channels.
[0039] In accordance with aspects of the present disclosure, the term uplink may refer to
a point-to-point transmission originating at a subordinate entity 204. Broadly, the
subordinate entity 204 is a node or device that receives scheduling control information,
including but not limited to scheduling grants, synchronization or timing information,
or other control information from another entity in the wireless communication network
such as the scheduling entity 202. A subordinate entity may be, or may reside within,
a base station, a network node, a UE, an access terminal, or any suitable node in
a wireless communication network.
[0040] FIG. 3 is a conceptual diagram illustrating an example of a hardware implementation
for a wireless communication device 300 employing a processing system 314. In accordance
with various aspects of the disclosure, an element, or any portion of an element,
or any combination of elements may be implemented with a processing system 314 that
includes one or more processors 304. For example, the wireless communication device
300 may be a scheduling entity 202, base station (BS), or any other suitable network
node, as illustrated in FIGs. 1, 2, and/or 4. Furthermore, the wireless communication
device 300 may be a subordinate entity 204, a UE, an IoE device, or any other suitable
network node, as illustrated in FIGs. 1, 2, and/or 4. Examples of processors 304 include
microprocessors, microcontrollers, digital signal processors (DSPs), field programmable
gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic,
discrete hardware circuits, and other suitable hardware configured to perform the
various functionality described throughout this disclosure. That is, the processor
304, as utilized in a wireless communication device 300, may be used to implement
any one or more of the processes described in FIGs. 10-13 of the present disclosure.
[0041] In this example, the processing system 314 may be implemented with a bus architecture,
represented generally by the bus 302. The bus 302 may include any number of interconnecting
buses and bridges depending on the specific application of the processing system 314
and the overall design constraints. The bus 302 links together various circuits including
one or more processors (represented generally by the processor 304), a memory 305,
and computer-readable media (represented generally by the computer-readable medium
306). The bus 302 may also link various other circuits such as timing sources, peripherals,
voltage regulators, and power management circuits, which are well known in the art,
and therefore, will not be described any further. A bus interface 308 provides an
interface between the bus 302 and one or more transceivers 310. The transceiver 310
(a communication interface) provides means for communicating with various other apparatus
over a transmission medium. In various examples, the transceivers 310 may include
one or more antennas, and in multi-antenna examples, may be enabled to determine an
angle from which a received signal arrives, or for beamforming of transmitted signals.
The transceiver 310 may include various sub-components configured to enable wireless
communication, including but not limited to one or more power amplifiers, a transmitter,
a receiver, filters, oscillators, etc. Further, depending upon the nature of the apparatus,
a user interface 312 (e.g., keypad, display, speaker, microphone, joystick, etc.)
may also be provided.
[0042] In one aspect of the disclosure, the processor 304 includes a coupled mode user control
block 320 and a decoupled mode user control block 322. The coupled mode user control
block may be configured to perform various functions for coupled mode communication,
and the decoupled mode user control block may be configured to perform various functions
for decoupled mode communication, as described in relation to FIGs. 5-13. In one example,
the coupled mode user control block 320 may include a control region block 324 and
a data region block 326. Similarly, the decoupled mode user control block 322 includes
a control region block 328 and a data region block 330. The control region blocks
324 and 328 may be configured to perform functions related to communication in control
regions 510 and 514 (see FIG. 5) of a subframe, and the data region blocks 326 and
330 may be configured to perform functions related to communication in data regions
512 and 516 (see FIG. 5) of a subframe.
[0043] In one aspect of the disclosure, the processor 304 includes a resource scheduling
block 332 that may be configured to schedule, allocate, and/or assign resources for
coupled mode users and decoupled mode users in communication with the apparatus 300
as described in relation to FIGs. 5-13. For example, the resource scheduling block
332 may be utilized to schedule traffic such that a first uplink burst from a coupled
mode user may be combined with a second uplink burst from a decoupled mode user on
a time division duplex (TDD) carrier utilizing non-orthogonal multiple access or orthogonal
multiple access as shown in FIGs. 5-8.
[0044] The processor 304 may further include a rise over thermal (RoT) block 334 and an
interference cancellation block 336. The RoT block 334 may be configured to perform
various functions to control RoT as described in FIG. 12, for example. The interference
cancellation block 336 may be configured to perform various interference cancellation
functions described in FIG. 11, for example.
[0045] The processor 304 is responsible for managing the bus 302 and general processing,
including the execution of software stored on the computer-readable medium 306. The
software, when executed by the processor 304, causes the processing system 314 to
perform the various functions described below in relation to FIGs. 5-13 for any particular
apparatus. The computer-readable medium 306 may also be used for storing data that
is manipulated by the processor 304 when executing software.
[0046] In one aspect of the disclosure, the software includes computer executable code or
instructions for configuring the processor 304 and/or the apparatus 300 to perform
the various functions described in FIGs. 5-13. For example, the software may include
coupled mode user control code 338, decoupled mode user control code 340, and multiplexing
control code 342. The coupled mode user code 338 when executed configures the processor
304 to perform various functions related to coupled mode users as described in FIGs.
5-13. The decoupled mode user code 340 when executed configures the processor 304
to perform various functions related to decoupled mode users as described in FIGs.
5-13. The multiplexing control code 342 when executed configures the processor 304
to perform various functions related to multiplexing coupled mode user traffic and
decoupled mode user traffic as described in FIGs. 5-13.
[0047] One or more processors 304 in the processing system may execute software. Software
shall be construed broadly to mean instructions, instruction sets, code, code segments,
program code, programs, subprograms, software modules, applications, software applications,
software packages, routines, subroutines, objects, executables, threads of execution,
procedures, functions, etc., whether referred to as software, firmware, middleware,
microcode, hardware description language, or otherwise. The software may reside on
a computer-readable medium 306. The computer-readable medium 306 may be a non-transitory
computer-readable medium. A non-transitory computer-readable medium includes, by way
of example, a magnetic storage device (e.g., hard disk, floppy disk, magnetic strip),
an optical disk (e.g., a compact disc (CD) or a digital versatile disc (DVD)), a smart
card, a flash memory device (e.g., a card, a stick, or a key drive), a random access
memory (RAM), a read only memory (ROM), a programmable ROM (PROM), an erasable PROM
(EPROM), an electrically erasable PROM (EEPROM), a register, a removable disk, and
any other suitable medium for storing software and/or instructions that may be accessed
and read by a computer. The computer-readable medium 306 may reside in the processing
system 314, external to the processing system 314, or distributed across multiple
entities including the processing system 314. The computer-readable medium 306 may
be embodied in a computer program product. By way of example, a computer program product
may include a computer-readable medium in packaging materials. Those skilled in the
art will recognize how best to implement the described functionality presented throughout
this disclosure depending on the particular application and the overall design constraints
imposed on the overall system.
[0048] FIG. 4 is a block diagram showing additional details of one example of a scheduling
entity 202 in communication with one example of a subordinate entity 204 in an access
network. In the DL, upper layer packets from the core network are provided to a controller/processor
475. The controller/processor 475 implements the functionality of the L2 layer. In
the DL, the controller/processor 475 provides header compression, ciphering, packet
segmentation and reordering, multiplexing between logical and transport channels,
and radio resource allocations to the subordinate entity 204 based on various priority
metrics. The controller/processor 475 is also responsible for hybrid automatic repeat
request (HARQ) operations, retransmission of lost packets, and signaling to the subordinate
entity 204.
[0049] The transmit (TX) processor 416 implements various signal processing functions for
the L1 layer (i.e., physical layer). The signal processing functions include coding
and interleaving to facilitate forward error correction (FEC) at the subordinate entity
204 and mapping to signal constellations based on various modulation schemes (e.g.,
binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), M-phase-shift
keying (M-PSK), M-quadrature amplitude modulation (M-QAM), etc.). The coded and modulated
symbols are then split into parallel streams. Each stream may then be mapped to an
OFDM subcarrier, multiplexed with a reference signal (e.g., pilot) in the time and/or
frequency domain, and then combined together using an Inverse Fast Fourier Transform
(IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The
OFDM stream is spatially precoded to produce multiple spatial streams. Channel estimates
from a channel estimator 474 may be used to determine the coding and modulation scheme,
as well as for spatial processing. The channel estimate may be derived from a reference
signal and/or channel condition feedback transmitted by the subordinate entity 204.
Each spatial stream may then be provided to a different antenna 420 via a separate
transmitter 418TX. Each transmitter 418TX may modulate an RF carrier with a respective
spatial stream for transmission.
[0050] At the subordinate entity 204, each receiver 454RX receives a signal through its
respective antenna 452. Each receiver 454RX recovers information modulated onto an
RF carrier and provides the information to the receive (RX) processor 456. The RX
processor 456 implements various signal processing functions of the L1 layer. The
RX processor 456 may perform spatial processing on the information to recover any
spatial streams destined for the subordinate entity 204. If multiple spatial streams
are destined for the subordinate entity 204, they may be combined by the RX processor
456 into a single OFDM symbol stream. The RX processor 456 then converts the OFDM
symbol stream from the time-domain to the frequency domain using a Fast Fourier Transform
(FFT). The frequency domain signal comprises a separate OFDM symbol stream for each
subcarrier of the OFDM signal. The symbols on each subcarrier, and the reference signal,
are recovered and demodulated by determining the most likely signal constellation
points transmitted by the scheduling entity 202. These soft decisions may be based
on channel estimates computed by the channel estimator 458. The soft decisions are
then decoded and deinterleaved to recover the data and control signals that were originally
transmitted by the scheduling entity 20 on the physical channel. The data and control
signals are then provided to the controller/processor 459.
[0051] The controller/processor 459 implements the L2 layer. The controller/processor can
be associated with a memory 460 that stores program codes and data. The memory 460
may be referred to as a computer-readable medium. In the UL, the controller/processor
459 provides demultiplexing between transport and logical channels, packet reassembly,
deciphering, header decompression, control signal processing to recover upper layer
packets from the core network. The upper layer packets are then provided to a data
sink 462, which represents all the protocol layers above the L2 layer. Various control
signals may also be provided to the data sink 462 for L3 processing. The controller/processor
459 is also responsible for error detection using an acknowledgement (ACK) and/or
negative acknowledgement (NACK) protocol to support HARQ operations.
[0052] In the UL, a data source 467 is used to provide upper layer packets to the controller/processor
459. The data source 467 represents all protocol layers above the L2 layer. Similar
to the functionality described in connection with the DL transmission by the scheduling
entity 202, the controller/processor 459 implements the L2 layer for the user plane
and the control plane by providing header compression, ciphering, packet segmentation
and reordering, and multiplexing between logical and transport channels based on radio
resource allocations by the scheduling entity 202. The controller/processor 459 is
also responsible for HARQ operations, retransmission of lost packets, and signaling
to the scheduling entity 202.
[0053] Channel estimates derived by a channel estimator 458 from a reference signal or feedback
transmitted by the scheduling entity 202 may be used by the TX processor 468 to select
the appropriate coding and modulation schemes, and to facilitate spatial processing.
The spatial streams generated by the TX processor 468 may be provided to different
antenna 452 via separate transmitters 454TX. Each transmitter 454TX may modulate an
RF carrier with a respective spatial stream for transmission. In some examples, in
the UL and DL directions, all or part of the transmission may utilize a single-carrier
waveform, an OFDM waveform, and any waveforms or modulation schemes described in this
disclosure in relation to an UL burst.
[0054] The UL transmission is processed at the scheduling entity 202 in a manner similar
to that described in connection with the receiver function at the subordinate entity
204. Each receiver 418RX receives a signal through its respective antenna 420. Each
receiver 418RX recovers information modulated onto an RF carrier and provides the
information to a RX processor 470. The RX processor 470 may implement the L1 layer.
[0055] The controller/processor 475 implements the L2 layer. The controller/processor 475
can be associated with a memory 476 that stores program codes and data. The memory
476 may be referred to as a computer-readable medium. In the UL, the control/processor
475 provides demultiplexing between transport and logical channels, packet reassembly,
deciphering, header decompression, control signal processing to recover upper layer
packets from the subordinate entity 204. Upper layer packets from the controller/processor
475 may be provided to the core network. The controller/processor 475 is also responsible
for error detection using an ACK and/or NACK protocol to support HARQ operations.
[0056] In one aspect of the disclosure, the above-described various components and functional
blocks of a scheduling entity 202 in FIG. 4 may be included in the apparatus 300.
In another aspect of the disclosure, the above described various components and functional
blocks of a subordinate entity 204 in FIG. 4 may be included in the apparatus 300.
[0057] In any wireless communication network, bi-directional communication is a desirable
feature. Frequently, duplexing communication onto the air channel is accomplished
utilizing frequency division duplex (FDD) or time division duplex (TDD). In FDD, a
pair of carriers is used, with each respective carrier being used to carry communication
signals in a different direction. In TDD, unpaired carriers are used. Here, duplexing
of uplink and downlink communication is achieved by time sharing the carrier, with
uplink and downlink communication occupying the carrier at different times.
[0058] In many modem wireless communication networks, significant portions of the spectrum
have been allocated by regulatory agencies in paired carriers for FDD. For new developing
technologies, if very high bandwidth communication is desired (e.g., 100 MHz, 300
Mhz, or more), however, these FDD technologies already utilize much of the spectrum,
and may not be as wideband as desired for much higher data rates. At higher frequencies,
including but not limited to millimeter wave (mmW) frequencies, TDD carriers may be
more available. Furthermore, such TDD carriers may be less expensive for a carrier
to obtain rights to use.
Common UL Burst in a TDD Carrier
[0059] When utilizing a TDD carrier, communication may in some examples be organized by
dividing the channel in the time domain into frames, with frames being further divided
into subframes. According to an aspect of the present disclosure, subframes may take
at least two general forms, referred to herein as an uplink-centric subframe structure
and a downlink-centric subframe structure. Here, a downlink-centric subframe is a
subframe where a majority of its time is used for communication in the downlink direction;
and an uplink-centric subframe is a subframe where a majority of its time is used
for communication in the uplink direction.
[0060] FIG. 5 is a schematic illustration showing a set of subframes 500 (e.g., a frame)
including one uplink-centric subframe 502 in every four subframes in one cycle, with
the remaining three out of four subframes being downlink-centric subframes 504. Of
course, this particular allocation of uplink-to-downlink centric subframes is merely
one example, and any proportion of uplink and downlink centric subframes may be utilized
in a particular implementation. In one example, a frame may have more uplink-centric
subframes 502 than downlink-centric subframes 504. In another example, a frame may
have more downlink-centric subframes 504 than uplink-centric subframes 502. In still
another example, a frame may have equal numbers of uplink-centric subframes 502 and
downlink-centric subframes 504.
[0061] In the illustrated examples, each subframe includes an uplink portion 506 utilized
for uplink communication and a downlink portion 508 utilized for downlink communication.
Here, a gap, a guard period, a guard interval, or a guard region may be utilized after
a downlink portion and before an uplink portion. Such a gap may facilitate switching
of the RF components of the transmitter and/or receiver, including re-tuning a phase-lock
loop and other radio functions/circuitry.
[0062] The illustrated downlink-centric subframe 504 includes a control region 510, which
may include a physical downlink control channel (PDCCH), and a data region 512, which
may include a physical downlink shared channel (PDSCH). The control region 510 may
include, among other things, scheduling information for informing scheduled devices
(e.g., a UE) which resources in the data region 512 include information for that particular
device.
[0063] The illustrated uplink-centric subframe 502 also includes a control region 514, which
may include a PDCCH, and a data region 516, which may include a physical uplink shared
channel (PUSCH) and/or other suitable channels corresponding to a regular uplink data
burst. The control region may include, among other things, scheduling information
for informing scheduled devices (e.g., a UE) which resources they may utilize for
uplink transmissions in the data region 516.
[0064] As illustrated in this example, both the uplink-centric subframe 502 and the downlink-centric
subframe 504 include a common uplink burst portion 518. In this example, the common
UL burst portion 518 is shown at the end of each subframe, but it is not necessarily
limited to the end, and in other examples the common UL burst may appear at any suitable
time within an uplink-centric subframe or a downlink-centric subframe, including at
the beginning of the subframe, or anywhere within the subframe. In some examples,
the common UL burst 518 may be structured in the same way in both the uplink-centric
subframes 502 and in the downlink-centric subframes 504.
[0065] In an aspect of the disclosure, the common UL burst 518 may be a relatively short
portion of the respective subframe, including, for example, two symbols. For example,
a two-symbol common UL burst may have a duration of around 31 µs. Of course, different
durations, and different numbers of symbols may be included in the common UL burst
within the scope of the present disclosure. That is, in a common UL burst within the
scope of the present disclosure, any suitable number of symbols may be utilized. However,
for clarity, within the present disclosure, a common UL burst including two symbols
is described in further detail, for example, in FIGs. 6 and 8.
[0066] Here, the common UL burst may be utilized to decouple the latency associated with
a control channel carried in the common UL burst, from the uplink/downlink pattern
selected in any given implementation. This decoupling is provided because a common
UL burst is present in both uplink-centric and downlink-centric subframes. For example,
in a TDD scheme, the downlink-centric subframes may typically appear much more frequently
than the uplink-centric subframes, since more regular network traffic may typically
be in the downlink direction. Further, in a typical deployment of a macrocell (e.g.,
an eNode B in an LTE deployment), the ratio between uplink and downlink traffic remains
relatively stable over time. That is, even though any single user's UL/DL ratio may
change rather drastically, when aggregated over large numbers of users, the overall
ratio generally remains nearly the same. However, unlike a macrocell small cells may
only serve very small numbers of users. Thus, for small cells, the total ratio between
UL and DL-centric subframes can largely vary over time. Thus, depending on the cell
size and the loading of the cell, the downlink and uplink patterns may change, and
the ratio between uplink and downlink-centric subframes may be any suitable ratio,
from one-to-one, or otherwise.
[0067] If the uplink-centric subframe is very rare, then, and downlink-centric subframes
dominate, there may be a problem in that a device with critical or time-sensitive
uplink information to transmit may need to wait for an extended period of time until
its uplink information can be transmitted. In particular, control information such
as channel quality information and feedback like packet acknowledgments may have a
time-sensitive nature, and their rapid transmission is important. Therefore, including
a common UL burst portion 518 in each subframe, including the downlink-centric subframes,
can help reduce or avoid such an extended latency for time-sensitive UL packets.
[0068] In a further aspect of the disclosure, such a common UL burst scheme provides for
the same channel structure to be utilized in unlicensed bands as well as licensed
bands. In unlicensed bands, users typically compete for resources, and are only able
to reserve use of the channel for a limited time before giving up the channel for
other users. Here, if a transmission is made just at the end of the time when a user
has the channel, and the device loses the channel before having an opportunity to
transmit an acknowledgment (or other time-critical uplink packet), the device may
be required to wait for an extended period to make such transmission, until the channel
can be reacquired. However, with the common UL burst channel structure, a resource
for such transmissions can be made available in every subframe, reducing or avoiding
such a delay for time-critical transmissions. In some aspects of the disclosure, the
common UL burst may be provided in every N predetermined number of subframes, where
N has a value of 2 or greater.
[0069] The common UL burst may additionally or alternatively be utilized for the transmission
of other control information, such as a scheduling request (SR). A scheduling request
may be an uplink transmission of information requesting a scheduling entity (e.g.,
a base station or eNB) to schedule uplink channel resources for the device to utilize
to transmit uplink data. These resources may appear within the regular UL burst region
illustrated in the uplink-centric subframe 502.
[0070] In still another example, the common UL burst portion 518 may additionally or alternatively
be utilized to carry a sounding reference signal (SRS). Within an unpaired TDD spectrum,
the channel that a scheduled device (e.g., a subordinate entity or UE) sees for downlink
transmissions is the same channel that a scheduling entity (e.g., an eNB) sees for
uplink transmissions. Therefore, channel characterization is somewhat simplified relative
to that for FDD channels. That is, the scheduling entity generally can acquire information
about the downlink channel as seen by the receiving or scheduled entity in order to
suitably schedule resources for that user using a TDD channel. While in an FDD channel
a UE measures the channel and sends feedback to the eNB to report its channel conditions,
in a TDD channel, the UE or scheduled device may transmit the SRS in an uplink transmission,
and the eNB or scheduling entity may utilize this transmission to characterize the
channel on its own for scheduling downlink transmissions. This SRS transmission is
generally desired to be transmitted with low latency, i.e., its transmission is somewhat
time critical. Thus, placement of the SRS within the common UL burst region can decouple
its latency from the downlink-to-uplink pattern or uplink-to-downlink pattern in a
given implementation.
[0071] Of course, the above are merely examples, and within the scope of the present disclosure,
the common UL burst may be utilized not only for such control information, but may
additionally or alternatively be utilized to carry uplink payload data (e.g., user
data) with a low latency requirement or predetermined latency. Here, such uplink payload
transmissions in the common UL burst region may be limited to transmitting devices
having sufficient power headroom for these transmissions. The power headroom of the
transmitting device or transmitter is a measure of the power margin available for
producing higher levels of output power for transmitting a given signal.
Coupled Mode vs. Decoupled Mode
[0072] Referring once again to FIG. 1, a UE 126 is illustrated relatively far from the base
station 112 (e.g., at or near a cell edge), while another UE 128 is illustrated relatively
close to the base station 112 (e.g., at or near a cell center). As described further
below, according to various aspects of the present disclosure, users located at the
cell center similar to the UE 128 may have sufficient power headroom to include data
transmissions (e.g., payload data) in the common UL burst, while users located at
the cell edge similar to the UE 126 may lack the power headroom to include data transmissions
in the common UL burst. Accordingly, in various aspects of the disclosure, users at
the cell edge may be configured to make their common UL burst transmissions in a coupled
mode that facilitates coverage extension for control information transmissions, while
users at the cell center may be configured to make their common UL burst transmissions
in a decoupled mode that facilitates user data transmissions in addition to control
information transmissions. The coupled mode and decoupled mode will be described in
more detail below in relation to FIGs. 6-8.
[0073] That is, these common UL burst regions within the subframes as described above may
be configured to support all users, including users near the cell center, as well
as users near a cell edge. For users at or near the cell edge (or weak coverage areas),
whose signal may be weak because they are relatively far from the base station or
scheduling entity, the content of the information within the common UL burst region
may be limited to certain control information such as the packet acknowledgments (ACK)
and scheduling requests (SR), which may be carried on a physical uplink control channel
(PUCCH). For these users, transmissions may be made in a certain mode, referred to
herein in the present disclosure as a coupled mode.
[0074] FIG. 6 is a schematic illustration showing an exemplary downlink-centric subframe
600 having a common UL burst configured for coupled mode and an exemplary downlink-centric
subframe 602 having a common UL burst configured for decoupled mode. The downlink-centric
subframes 600 and 602 may be the same as the downlink-centric subframes 504 of FIG.
5. These coupled and decoupled modes are described in further detail below.
[0075] In the coupled mode, illustrated by the downlink-centric subframe 600, the SRS 604
may be re-used to serve the purpose of the demodulation reference signal (DM-RS),
so that demodulation of the information bits in the common UL burst may be accomplished
with the coupled SRS/DM-RS signal. That is, in coupled mode transmissions, DM-RS symbols
that are separate from or decoupled from the SRS symbols may be omitted. In this way,
for coupled mode transmissions, the additional power that may be consumed by the transmission
of the DM-RS pilot symbols may be conserved. Thus, coupled mode transmissions (e.g.,
SRS/DM-RS coupled transmission) may have a reduced power consumption.
[0076] In particular, although a given device may have a multi-antenna configuration and
a capability for multiple-input multiple-output (MIMO) transmissions, cell edge users
may transmit only using their strongest antenna or their dominant precoder, without
utilizing MIMO. For this reason, when such users are configured to transmit the common
UL burst in the coupled mode, the SRS bits and the DM-RS bits need not be precoded
separately. Therefore, in an aspect of the present disclosure, the SRS may be utilized
for the purpose of a DM-RS, and accordingly, a separate DM-RS may be omitted. Here,
to facilitate the use of the SRS as a demodulation reference signal, in an aspect
of the disclosure, the symbol or symbols 606 carrying control information (e.g., ACK
or SR) may occupy the same bandwidth as that of the symbol or symbols carrying the
SRS 604.
[0077] The bandwidth of the symbols may be maintained as the same for coupled mode users
because the received power of the UL transmissions from these users may be relatively
weak, and therefore, these users' transmissions may be non-orthogonal to one another.
Because these users' transmissions are weak, they generally do not substantially interfere
with one another and accordingly, their transmissions may be superposed or overlap
(non-orthogonal) in frequency and time while still being recoverable by the receiving
base station.
[0078] Furthermore, according to some examples only control information (e.g., PUCCH) may
be transmitted in the common UL burst in the coupled mode. That is, in these examples,
data information (e.g., PUSCH) may be omitted from the common UL burst in the coupled
mode. This is because the coupled mode users are generally devices that are relatively
far from the base station or scheduling entity, so the power of the UL transmissions
when they are received at the base station is relatively weak, and may be insufficient
to support the data traffic in the short common UL burst. In some examples, both data
information and control information may be transmitted in the common UL burst in the
coupled mode. In this case, the data and SRS may be beamformed in the same way.
[0079] Therefore, as illustrated, in the common UL burst, for coupled mode users, an SRS
and what may be considered "critical" (e.g., latency-sensitive or mission-critical)
control information may be included. This control information (e.g., PUCCH) may include,
for example, packet acknowledgments (ACK) and scheduling request (SR) packets.
[0080] On the other hand, a decoupled mode, illustrated by the downlink-centric subframe
602, may be targeted for users who may be relatively close to the scheduling entity
or base station, because their signal may be more easily received by the base station.
These devices generally have sufficient power headroom to accommodate the additional
pilot or reference signal transmissions associated with the DM-RS. Therefore, if a
user or subordinate entity is relatively close to the cell center or close to the
base station or scheduling entity, the scheduling entity may accumulate enough energy
even during the short common UL burst to decode the uplink payload data in the common
UL burst region. Accordingly, in an aspect of the present disclosure, the decoupled
mode is provided, e.g., for these users that are relatively close to the cell center
or close to the base station or scheduling entity.
[0081] In the decoupled mode, the UE or subordinate entity may be enabled to opportunistically
transmit uplink payload data having low latency requirements. That is, by virtue of
the decoupled mode, devices operating in decoupled mode may be enabled to transmit
information on a PUSCH within the common UL burst region of uplink-centric subframes
and downlink-centric subframes. The present disclosure refers specifically to the
PUSCH as an example, however, it is to be understood that this term is merely included
for clarity, and aspects of the disclosure may utilize any suitable physical uplink
channel for carrying traffic payload data.
[0082] Unlike in the coupled mode, in the decoupled mode, the bandwidth of the SRS symbol
608 need not be the same as the bandwidth of the second symbol 610, which may include
PUCCH (control) as well as PUSCH (data) information. That is, because the SRS may
not be used for demodulating the PUCCH and PUSCH, and the DM-RS is utilized for this
purpose, the second symbol 610 can have a bandwidth that differs from the first symbol
608 including the SRS.
[0083] Within the present disclosure, the name "decoupled" with reference to the decoupled
mode generally refers to a decoupling of the SRS from a demodulation reference signal
(DM-RS). In order to demodulate the PUCCH or PUSCH, a pilot or reference signal may
be needed. Here, the DM-RS provides a pilot that may be utilized to demodulate the
PUCCH/PUSCH bits. In a decoupled mode, the SRS and the DM-RS are separate signals,
and have different transmission characteristics. Thus, the SRS and DM-RS are decoupled
from one another when a scheduled or subordinate entity operates in the decoupled
mode.
[0084] In some examples, because decoupled mode users may generally be those that are relatively
close to the scheduling entity or base station, those users may utilize multiple-input
multiple-output (MIMO) or other beamforming techniques in their uplink transmissions.
[0085] That is, the subordinate entities 204 (e.g., UE 126/128, wireless communication devices
300, user equipment or UEs, etc.) may have multiple antennas supporting Multiple Input
Multiple Output (MIMO) technology. The use of MIMO technology enables the wireless
communication devices to exploit the spatial domain to support spatial multiplexing,
beam-forming, and transmit diversity. Spatial multiplexing may be used to transmit
different streams of data simultaneously on the same frequency. The data streams may
be transmitted to a single receiving device to increase the data rate or to multiple
receiving devices to increase the overall system capacity. This is achieved by spatially
precoding each data stream (i.e., applying a scaling of an amplitude and a phase)
and then transmitting each spatially precoded stream through multiple transmit antennas.
The spatially pre-coded data streams arrive at the receiving device(s) with different
spatial signatures, which enables each of the receiving devices to recover the one
or more data streams destined for that device.
[0086] Spatial multiplexing is generally used when channel conditions are good. When channel
conditions are less favorable, beamforming may be used to focus the transmission energy
in one or more directions. This may be achieved by spatially precoding the data for
transmission through multiple antennas.
[0087] Specifically referring to the common UL burst described above, in order to use MIMO,
the transmitted information is suitably configured utilizing a certain precoding matrix.
That is, in an aspect of the present disclosure, to enable MIMO or beamforming for
the uplink data within the common UL burst, the uplink data transmitted within this
common UL burst may be precoded utilizing a selected precoding matrix.
[0088] However, in a further aspect of the disclosure, the SRS transmission within the common
UL burst may not be beamformed or precoded for MIMO transmission. For decoupled mode
users who wish to use MIMO in their uplink transmissions, the pilot (i.e., the SRS)
generally cannot be used as the demodulation reference signal (DM-RS) for demodulating
the data, since the data and the pilot use different precoding, and are accordingly
beamformed differently. Therefore, the SRS and its precoding or beamforming is decoupled
from the DM-RS and its precoding or beamforming.
Multiple Access of Coupled Mode and Decoupled Mode Users
[0089] In an access network such as the one illustrated in FIG. 1, with one or more decoupled
mode users (e.g., UEs 128) operating simultaneous to one or more coupled mode users
(e.g., UEs 126), a suitable multiple access scheme is needed to enable the base station
112 or scheduling entity to properly receive and decode the differently formatted
transmissions from coupled mode users and decoupled mode users.
[0090] Therefore, according to some aspects of the present disclosure, two different multiple
access algorithms are disclosed for coupled and decoupled mode transmissions utilizing
a common UL burst. In the discussion that follows, these algorithms are discussed
in turn. First, a non-orthogonal multiple access scheme, and second, an orthogonal
multiple access scheme. With these schemes, coupled mode and decoupled mode transmissions
may occur simultaneously from a plurality of devices.
Non-Orthogonal Multiple Access
[0091] FIG. 7 is a schematic illustration of a common UL burst 700 utilizing a non-orthogonal
multiple access algorithm supporting the sharing of the channel by one or more coupled
mode users, and as illustrated, two decoupled mode users. For example, the coupled
mode users may be any of the devices located near the cell edge, and the decoupled
mode users may be any of the devices located near the base station, as illustrated
in FIG. 1. These numbers of coupled and decoupled mode users are merely exemplary
in nature, and any number of users in either mode may appear within the scope of the
present disclosure.
[0092] In the first symbol 702, all users in both coupled mode and decoupled mode may transmit
their SRS, occupying the entire bandwidth. In the example of FIG. 7, the entire bandwidth
is 80 MHz, although it is to be understood that this is merely one example, and any
suitable bandwidth may be utilized in a particular implementation within the scope
of the present disclosure. Here, the coupled mode and decoupled mode transmissions
are non-orthogonal to one another, being superposed or overlapping one another's transmissions.
The SRS transmissions of coupled mode users and decoupled mode users may be differentiated
by use of unique (or at least user-specific) or different scrambling codes according
to conventional CDMA techniques known to those of ordinary skill in the art.
[0093] In the second symbol 704, coupled mode users may transmit control information, e.g.,
utilizing a PUCCH. For the coupled mode users' PUCCH transmissions 706, each coupled
mode user's transmission occupies all of the subcarriers in that symbol. Thus, the
UL transmissions of the coupled mode users overlap with one another, and further overlap
with decoupled mode users' UL transmissions.
[0094] Because the PUCCH for the coupled mode users is spread across all of the subcarriers,
the communication of the decoupled mode users (i.e., their PUCCH and/or PUSCH) is
non-orthogonal to the communication of the coupled mode users.
[0095] Therefore, in the second symbol 704, transmissions from coupled mode users may differ
from transmissions from decoupled mode users. That is, as described above, coupled
mode users may transmit their PUCCH (e.g., control information) using the same bandwidth
as the SRS transmission. For example, coupled mode users may transmit their PUCCH
to occupy the entire wide band or channel bandwidth. Each coupled mode user's PUCCH
transmission in the second symbol 704 is non-orthogonal to that of other coupled mode
users, and the coupled mode users' PUCCH transmissions may be differentiated by utilizing
user-specific or different sequences or scrambling codes, known to those of ordinary
skill in the art.
[0096] As for decoupled mode users, their transmissions in the second symbol 704 include
a control region, for example, including a PUCCH 708, and optionally include a data
region 710, including a PUSCH 710.
[0097] FIG. 7 is an exemplary illustration of multiple access for common UL burst transmissions
by three or more users in accordance with one example. In the illustrated example,
one coupled mode user is transmitting in the same common UL burst as two decoupled
mode users (user 1 and user 2). Of course, any number of coupled and decoupled mode
users may transmit during a given common UL burst 700, and these numbers are merely
provided for illustrative purposes.
[0098] As seen in FIG. 7, both the coupled mode users and decoupled mode users share the
first symbol 702 by transmitting their respective SRS, including each user's unique
scrambling code. Thus, the receiving entity (e.g., a base station or scheduling entity)
can differentiate the respective users' SRS by utilizing user-specific sequences or
scrambling codes. In the second symbol 704, the coupled mode user transmits its PUCCH
706 occupying the entire wide band, i.e., having the same bandwidth as the transmission
of the SRS in the first symbol 702. This coupled mode user's PUCCH transmission is
scrambled with the user's unique scrambling code, for achieving multiple access with
any other coupled mode user transmitting their own PUCCH in this symbol of the common
UL burst.
[0099] The decoupled mode users' transmissions in the second symbol 704 of the common UL
burst differ from one another. In the control region, both of the users may transmit
their respective PUCCH 708 in an unscheduled manner, superposed over one another as
well as that region or bandwidth of the coupled mode users' transmissions. Here, the
PUCCH 708 of the decoupled mode users are non-orthogonal to one another, being differentiated
by being scrambled with the respective users' unique scrambling codes, for achieving
multiple access utilizing conventional CDMA techniques. However, the PUSCH or payload
data of each decoupled mode user occupies scheduled resources (e.g., different frequency
subcarriers), so that decoupled mode users' data region transmissions 710-1 and 710-2
may be orthogonal to one another. That is, each decoupled mode user may transmit a
scheduling request, for example, within the PUCCH region of a common UL burst. In
response, the network may transmit a scheduling grant to the decoupled mode user,
assigning a particular set of resources in the data region 710 of a common UL burst.
Accordingly, the decoupled mode user may utilize the assigned resources for transmission
of its PUSCH 710 in the data region (e.g., second symbol 704) of a common UL burst.
Here, multiple access among the decoupled mode users may be achieved by way of Orthogonal
Frequency-Division Multiple Access (OFDMA), with the scheduled transmissions occupying
distinct sets of subcarriers within the data region of the common UL burst.
[0100] It may be observed that the decoupled mode users' control and data transmissions
708 and 710 (710-1 and 710-2) in the second symbol 704 are non-orthogonal to the coupled
mode users' PUCCH transmissions 706. Accordingly, there may be interference between
the respective coupled mode and decoupled mode users. In particular, because the decoupled
mode may be applied to users near the cell center or base station, the power of their
transmissions received at the base station may be quite strong, and may create substantial
interference to the PUCCH transmissions from the coupled mode users, whose transmissions
from near the cell edge may be weak at the receiving base station or scheduling entity.
According to various aspects of the present disclosure, the receiving base station
or scheduling entity may account for this interference utilizing a suitable interference
handling algorithm or technique.
Interference Handling
[0101] In one aspect of the present disclosure, a successive interference cancellation (SIC)
receiver may be employed at the receiving scheduling entity. SIC receivers are generally
known to those of ordinary skill in the art, and are implemented in many conventional
base stations, e.g., those deployed in existing CDMA networks. In one example, a SIC
receiver may be implemented with the interference cancellation block 336 of FIG. 3.
[0102] To account for the interference between coupled and decoupled mode users, the scheduling
entity may utilize the SIC receiver to first decode the signals received from the
relatively high power decoupled mode users. Once decoded, these transmissions may
be reconstructed, and cancelled to remove their signal from the received waveform
using interference cancellation techniques known to those of ordinary skill in the
art. Once the decoupled mode users' signals are cancelled out or removed, the scheduling
entity may utilize the SIC receiver to decode the relatively weak signals received
from the coupled mode users.
[0103] In another aspect of the disclosure, rise over thermal (RoT) control may be employed
by the receiving scheduling entity to handle interference between coupled mode users
and decoupled mode users. RoT is the ratio between the total power received at the
scheduling entity and the thermal noise. RoT is well-known to those of ordinary skill
in the art, and many existing networks employ a variety of techniques to manage and
control the RoT that results from the transmissions of network users.
[0104] The signals received from coupled mode users may be relatively weak, and their transmissions
are spread across the bandwidth. Thus, the RoT resulting from these coupled mode transmissions
may be relatively low. However, the RoT arising from the decoupled mode users, particularly
in relation to their PUSCH or data region transmissions, may become problematic. Accordingly,
as long as these decoupled mode users' transmissions are suitably controlled, the
total RoT that they contribute may be sufficiently moderated or controlled so that
all users' transmissions (coupled mode and decoupled mode transmissions) may be decoded
without using signal cancellation techniques or a SIC receiver.
[0105] Therefore, according to an aspect of the disclosure, the scheduling entity may utilize
an RoT control algorithm to actively control one or more transmission parameters of
the decoupled mode users to moderate the RoT contributed from their transmissions.
In one example, the RoT control algorithm may be implemented at the RoT controller
of FIG. 3. The scheduling entity may specify a suitable modulation and coding scheme
(MCS) for each decoupled mode user for their PUSCH or data region transmissions such
that their RoT contribution may be controlled.
[0106] In another example, the scheduling entity or the RoT controller may employ power
control of the PUCCH transmissions of both the coupled mode users and the decoupled
mode users to reduce the RoT resulting from their respective PUCCH transmissions.
That is, although the RoT resulting from coupled mode users may be relatively small,
if there are large numbers of these coupled mode users transmitting in the common
UL burst, they can still contribute to a large RoT. Therefore, controlling (e.g.,
reducing) the power of the coupled mode users' PUCCH transmissions can moderate the
RoT. Similarly, the PUCCH transmissions of the decoupled mode users may be power controlled
by the scheduling entity utilizing the RoT controller.
[0107] For example, the scheduling entity may set a suitable RoT threshold, and may transmit
one or more control signalings to users to suitably configure their MCS and/or their
transmission power such that their transmissions in the common UL burst do not cause
the RoT to exceed the RoT threshold. These control signalings for controlling the
RoT may be broadcast to a set of users, particularly for the SRS and for the control
regions of a subframe where the transmission resources may be shared by multiple users.
In another example, these control signalings for controlling the RoT may be unicast
to a particular user, particularly for the PUSCH transmissions by decoupled mode users
that transmit utilizing scheduled resources. A receiver (scheduling entity) of the
UL transmissions can demodulate, differentiate, and estimate the received power of
each individual user, for example, coupled mode users and decoupled mode users. Therefore,
the scheduling entity can determine which user's transmission is causing undesirably
large RoT.
Orthogonal Multiple Access
[0108] FIG. 8 is a schematic illustration of a common UL burst 800 utilizing an orthogonal
multiple access algorithm supporting the sharing of the channel by one or more coupled
mode users, and one or more decoupled mode users.
[0109] In this example, in the same way as for the non-orthogonal multiple access scheme
described above, the first symbol 802 includes SRS transmissions shared by all users
in both coupled mode and decoupled mode. That is, the first symbol 802 including the
SRS transmissions may be substantially the same in the orthogonal scheme as in the
non-orthogonal scheme shown in FIG. 7.
[0110] For coupled mode users, the second symbol 804 in the common UL burst includes a wideband
transmission 806 of the PUCCH, occupying the same bandwidth (e.g., 80 MHz in FIG.
8) as the SRS in the first symbol 802. That is, the PUCCH of the coupled mode users
may span the entire available bandwidth. Furthermore, for coupled mode users, the
second symbol 804 in the common UL burst is configured as a single carrier waveform.
Therefore, for orthogonal multiple access with decoupled mode users, whose transmissions
may be a higher power OFDMA waveform and utilizing scheduled resources, certain considerations
must take place for the symbol structure in each mode.
[0111] According to an aspect of the present disclosure, interleaved frequency division
multiple access (IFDMA) may be utilized to enable orthogonal multiple access for coupled
mode users and decoupled mode users in a common UL burst transmission as illustrated
in FIG. 8.
[0112] In the common UL burst 800, the resources may be allocated in the frequency domain
according to a set of subcarriers or tones. By implementing IFDMA, a coupled mode
user's transmission 806 may, for example, occupy every other tone, in a periodic fashion.
In this way, the PUCCH transmission in the second symbol 804 may be a single carrier
waveform. In another example, a single carrier transmission may be carried out by
transmitting in every third tone rather than every other tone. This may enable the
coupled mode users' transmissions to be spread across the entire carrier and occupy
the same bandwidth as that of the SRS (so that the SRS may be utilized as the demodulation
pilot for the coupled mode users' PUCCH), while still maintaining suitable frequency
diversity across the PUCCH, which is important for reliability of transmission for
the weak-signal coupled mode users.
[0113] In this way, the tones or subcarriers in between those occupied by coupled mode users
may be available for data transmission by the decoupled mode users. That is, because
the decoupled mode users are configured to utilize an OFDM waveform for their PUCCH/PUSCH
transmission, these decoupled mode users may fit their transmissions 808 in between,
or interleaved with, the tones 806 occupied by the coupled mode users.
[0114] A characteristic of OFDM transmissions is that essentially arbitrary subcarrier assignments
may be given to users using OFDM. Accordingly, in an aspect of the present disclosure,
decoupled mode users may be configured to transmit their PUCCH and (if transmitted)
their PUSCH in the tones 808 or subcarriers unoccupied by the coupled mode users.
[0115] Therefore, in another aspect of the present disclosure illustrated in FIG. 9, for
every UL resource block 900 having M contiguous tones for transmitting the second
symbol of a common UL burst, this resource block may have k tones reserved for coupled
mode users, and (M-k) tones reserved for decoupled mode users. For the coupled mode
users, multiple access to the k tones may be achieved in an orthogonal manner or in
a non-orthogonal manner. For orthogonal multiple access among the coupled mode users,
it may be the case, for example, that a first user (user 1) occupies every third tone
(e.g., tones 1, 4, 7, 10, 13...) and a second user (user 2) occupies every third tone
(e.g., tones 2, 5, 8, 11, 14...). In this way, both users 1 and 2 maintain a single
carrier waveform by occupying every third tone of the resource block in a periodic
fashion, while occupying the same bandwidth as that of the SRS in the first symbol.
Still, users 1 and 2 are orthogonal to one another, while leaving some tones (e.g.,
tones 3, 6, 9, 12, 15...) for the decoupled mode users' transmissions in the common
UL burst.
[0116] This scheme can be extended to accommodate any number of orthogonal coupled mode
users, each occupying a different subset of the k tones reserved for coupled mode
users. Moreover, each subset of the k tones may be shared by a cluster of users non-orthogonally
occupying those same subset of k tones. That is, referring to the example described
previously, two or more users may occupy tones 1, 4, 7, 10, 13..., k.
[0117] FIG. 10 is a flowchart illustrating a non-orthogonal multiple access method 1000
for coupled mode and decoupled mode users in wireless communication in accordance
with an aspect of the disclosure. For example, this method may be performed by any
scheduling entity, e.g., as illustrated in FIGs. 1-4 in a common UL burst over a time
division duplex (TDD) carrier. At block 1002, a scheduling entity may utilize a transceiver
310 (see FIG. 3) and/or a coupled mode user control block 320 to receive a first uplink
burst from a coupled mode user within each of a downlink-centric subframe and an uplink-centric
subframe on the TDD carrier. For example, the first uplink burst may be received in
the DL-centric subframe and UL-centric subframe shown in FIG. 5. In one aspect of
the disclosure, the first uplink burst may be the PUCCH transmission 706 of a coupled
mode user shown in FIG. 7.
[0118] At block 1004, the scheduling entity may utilize the transceiver 310 and/or a decoupled
mode user control block 322 to receive a second uplink burst from a decoupled mode
user within each of the downlink-centric subframe and the uplink-centric subframe
on the TDD carrier. For example, the second uplink burst may be received in the DL-centric
subframe and UL-centric subframe shown in FIG. 5. In one aspect of the disclosure,
the second uplink burst includes the PUCCH 708 and/or PUSCH 710 of a decoupled mode
user shown in FIG. 7. The first uplink burst from the coupled mode user is combined
with the second uplink burst from the decoupled mode user on the TDD carrier utilizing
non-orthogonal multiple access. That is, the first uplink burst and the second uplink
burst overlap in frequency or bandwidth.
[0119] FIG. 11 is a flowchart illustrating an interference cancellation method 1100 for
handling interference between non-orthogonal uplink bursts from coupled mode users
and decoupled mode users in accordance with an aspect of the disclosure. In one example,
this method 1100 may be performed by a scheduling entity illustrated in any of FIGs.
1-4 when performing the non-orthogonal multiple access method 1000 of FIG. 10.
[0120] In one scenario, a scheduling entity receives a first uplink burst from a coupled
mode user and a second uplink burst from a decoupled mode user similar to those shown
in FIG. 7. At block 1102, the scheduling entity stores the received first uplink burst
and second uplink burst in memory. For example, the scheduling entity may utilize
the memory 305 (see FIG. 3) to store the uplink bursts. At block 1104, the scheduling
entity decodes the second uplink burst from the decoupled mode user. For example,
the scheduling entity may utilize a receiver 418RX and/or an RX processor 470 (see
FIG. 4) to decode and recover the information of the second uplink burst.
[0121] At block 1106, the scheduling entity applies interference cancellation to remove
the second uplink burst from the stored received bursts. In one example, the scheduling
entity may utilize an interference cancellation block 336 (see FIG. 3) to perform
successive interference cancellation (SIC) techniques, which are known in the art,
to remove the second uplink burst from the received bursts. After applying SIC or
other suitable interference cancellations, the stored uplink bursts in the memory
contain data corresponding to the first uplink burst. At block 1108, the scheduling
entity decodes the first uplink burst from the interference cancelled uplink bursts.
For example, the scheduling entity may utilize the receiver 418RX and/or an RX processor
470 (see FIG. 4) to decode and recover the information of the first uplink burst.
[0122] FIG. 12 is a flowchart illustrating an RoT based interference handling method 1200
for handling interference between non-orthogonal uplink bursts from coupled mode users
and decoupled mode users in accordance with an aspect of the disclosure. In one example,
this interference handling method 1200 may be performed by a scheduling entity illustrated
in any of FIGs. 1-4 when performing the non-orthogonal multiple access method 1000
of FIG. 10.
[0123] In one scenario, a scheduling entity receives a first uplink burst from a coupled
mode user and a second uplink burst from a decoupled mode user similar to those shown
in FIG. 7. At block 1202, the scheduling entity determines an RoT for example utilizing
an RoT block 334 (see FIG. 3). RoT may be determined as a ratio between the total
interference or total wideband power received and the thermal noise. At decision block
1204, the scheduling entity may utilize the RoT block 334 to determine whether or
not the RoT is greater than a predetermined threshold value. An example of the RoT
threshold value may be 6 dB. If the RoT is greater than the threshold, at block 1206,
the scheduling entity utilizes the RoT block 334, coupled mode user control block
320, and/or decoupled mode user control block 322 to modulate the RoT contribution
of the coupled mode users and/or decoupled mode users.
[0124] For example, the scheduling entity may transmit one or more control messages in the
PDCCH to one or more decoupled mode users and/or coupled mode users to reduce the
UL power in one or more UL channels (e.g., PUCCH and PUSCH). The control message may
include one or more transmit power control (TPC) commands or other suitable power
control commands. In response to a TPC command, the decoupled mode user and/or coupled
mode user may increase, decrease or maintain the UL transmit power. Therefore, using
TPC commends, the scheduling entity may moderate the RoT contribution of the coupled
mode users and decoupled mode users.
[0125] FIG. 13 is a flowchart illustrating an orthogonal multiple access method 1300 for
coupled mode and decoupled mode users in wireless communication in accordance with
an aspect of the disclosure. For example, this method may be performed at any scheduling
entity as illustrated in FIGs. 1-4 over a TDD carrier. At block 1302, a scheduling
entity may utilize a transceiver 310 (see FIG. 3) and/or a coupled mode user control
block 320 to receive a first uplink burst from a coupled mode user within each of
a downlink-centric subframe and an uplink-centric subframe on the TDD carrier. For
example, the first uplink burst may be received in the DL-centric subframe and UL-centric
subframe shown in FIG. 5. In one aspect of the disclosure, the first uplink burst
may be the PUCCH transmission 806 of a coupled mode user shown in FIG. 8.
[0126] At block 1304, the scheduling entity may utilize the transceiver 310 and/or a decoupled
mode user control block 322 to receive a second uplink burst from a decoupled mode
user within each of the downlink-centric subframe and the uplink-centric subframe
on the TDD carrier. For example, the second uplink burst may be the PUCCH 808 of a
decoupled mode user shown in FIG. 8. The first uplink burst from the coupled mode
user is combined with the second uplink burst from the decoupled mode user on the
TDD carrier utilizing orthogonal multiple access as described above for example in
FIG. 8. That is, the first uplink burst and the second uplink burst are transmitted
in non-overlapping frequencies or carriers.
[0127] In one aspect of the disclosure, the first uplink burst from the coupled mode user
includes at least one symbol with uplink control information. For example, the symbol
may be the symbol 804 shown in FIG. 8. The uplink control information may be structured
as a single carrier waveform using interleaved frequency division multiple access
(IFDMA) occupying a subset of subcarriers across resource blocks in the TDD carrier.
For example, the uplink control information may be similar to the IFDMA uplink transmission
806 shown in FIG. 8.
[0128] In one aspect of the disclosure, the second uplink burst from the decoupled mode
user includes at least one symbol with uplink control information. For example, the
uplink control information may be structured as an orthogonal frequency division multiplexed
(OFDM) waveform 808 interleaved between at least a portion of the subcarriers making
up the uplink control information corresponding to the first uplink burst 806 from
the coupled mode user as illustrated in FIG. 8.
[0129] FIG. 14 is a flowchart illustrating a non-orthogonal multiple access method 1400
operable at a coupled mode subordinate entity for wireless communication over a TDD
carrier in accordance with an aspect of the disclosure. For example, this method may
be performed by any subordinate entity, e.g., as illustrated in FIGs. 1-4 in a common
UL burst over a TDD carrier.
[0130] At block 1402, a subordinate entity prepares a first uplink burst including a sounding
reference signal (SRS) in a first symbol and control information in a second symbol
configured to be demodulated based on the SRS. For example, a subordinate entity 204
(see FIG. 4) may utilize one or more of a TX processor 468, a channel estimator, and/or
a data source 467 to prepare a first uplink burst 700 (see FIG. 7). At block 1404,
the subordinate entity may utilize the transmitters 454TX to transmit the first uplink
burst within a subframe on the TDD carrier. The first uplink burst is combined with
a second uplink burst from a decoupled mode subordinate entity on the TDD carrier
utilizing non-orthogonal multiple access. For example, the first uplink burst may
be the PUCCH 706 (FIG. 7) of coupled mode users, and the second uplink burst may be
the PUCCH 708 and/or PUSCH 710 (FIG. 7) of decoupled mode users.
[0131] FIG. 15 is a flowchart illustrating an orthogonal multiple access method 1500 operable
at a coupled mode subordinate entity for wireless communication over a TDD carrier
in accordance with an aspect of the disclosure. For example, this method may be performed
by any subordinate entity, e.g., as illustrated in FIGs. 1-4 in a common UL burst
over a TDD carrier.
[0132] At block 1502, a subordinate entity prepares a first uplink burst including a sounding
reference signal (SRS) in a first symbol and control information in a second symbol
configured to be demodulated based on the SRS. For example, a subordinate entity 204
(see FIG. 4) may utilize one or more of a TX processor 468, a channel estimator, and/or
a data source 467 to prepare a first uplink burst 800 (see FIG. 8). At block 1504,
the subordinate entity may utilize the transmitters 454TX to transmit the first uplink
burst within a subframe on the TDD carrier. The first uplink burst is combined with
a second uplink burst from a decoupled mode subordinate entity on the TDD carrier
utilizing orthogonal multiple access. For example, the first uplink burst may be the
PUCCH 806 (FIG. 8) of coupled mode users, and the second uplink burst may be the PUCCH/PUSCH
808 (FIG. 8) of decoupled mode users.
[0133] FIG. 16 is a flowchart illustrating a non-orthogonal multiple access method 1600
operable at a decoupled mode subordinate entity for wireless communication over a
TDD carrier in accordance with an aspect of the disclosure. For example, this method
may be performed by any subordinate entity, e.g., as illustrated in FIGs. 1-4 in a
common UL burst over a TDD carrier.
[0134] At block 1602, a subordinate entity prepares a first uplink burst including a sounding
reference signal (SRS) in a first symbol and a demodulation reference signal (DM-RS)
in a second symbol decoupled from the SRS. For example, a subordinate entity 204 (see
FIG. 4) may utilize one or more of a TX processor 468, a channel estimator, and/or
a data source 467 to prepare a first uplink burst 700 (see FIG. 7). At block 1604,
the subordinate entity may utilize the transmitters 454TX to transmit the first uplink
burst within a subframe on the TDD carrier. The first uplink burst is combined with
a second uplink burst from a coupled mode subordinate entity on the TDD carrier utilizing
non-orthogonal multiple access. For example, the second uplink burst may be the PUCCH
706 (FIG. 7) of coupled mode users, and the first uplink burst may be the PUCCH 708
and/or PUSCH 710 (FIG. 7) of decoupled mode users.
[0135] FIG. 17 is a flowchart illustrating an orthogonal multiple access method 1700 operable
at a decoupled mode subordinate entity for wireless communication over a TDD carrier
in accordance with an aspect of the disclosure. For example, this method may be performed
by any subordinate entity, e.g., as illustrated in FIGs. 1-4 in a common UL burst
over a TDD carrier.
[0136] At block 1702, a subordinate entity prepares a first uplink burst including a sounding
reference signal (SRS) in a first symbol and a demodulation reference signal (DM-RS)
in a second symbol decoupled from the SRS. For example, a subordinate entity 204 (see
FIG. 4) may utilize one or more of a TX processor 468, a channel estimator, and/or
a data source 467 to prepare a first uplink burst 800 (see FIG. 8). At block 1704,
the subordinate entity may utilize the transmitters 454TX to transmit the first uplink
burst within a subframe on the TDD carrier. The first uplink burst is combined with
a second uplink burst from a coupled mode subordinate entity on the TDD carrier utilizing
orthogonal multiple access. For example, the second uplink burst may be the PUCCH
806 (FIG. 8) of coupled mode users, and the first uplink burst may be the PUCCH/PUSCH
808 (FIG. 8) of decoupled mode users.
[0137] In the above-described processes and procedures in relation to FIGs. 10-17, the uplink
common burst may occur in both the downlink-centric subframes and uplink-centric subframes.
[0138] It is to be understood that the specific order or hierarchy of steps in the methods
disclosed is an illustration of exemplary processes. Based upon design preferences,
it is understood that the specific order or hierarchy of steps in the methods may
be rearranged. The accompanying method claims present elements of the various steps
in a sample order, and are not meant to be limited to the specific order or hierarchy
presented unless specifically recited therein.
[0139] As those skilled in the art will readily appreciate, various aspects described throughout
this disclosure may be extended to any suitable telecommunication system or systems,
network architectures, and communication standards. By way of example, various aspects
may be applied to UMTS systems such as W-CDMA, TD-SCDMA, and TD-CDMA. Various aspects
may also be applied to systems employing Long Term Evolution (LTE) (in FDD, TDD, or
both modes), LTE-Advanced (LTE-A) (in FDD, TDD, or both modes), LTE-U, CDMA2000, Evolution-Data
Optimized (EV-DO), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16
(WiMAX), IEEE 802.20, Bluetooth, and/or other suitable systems, including those described
by yet-to-be defined wide area network standards. The actual telecommunication standard,
network architecture, and/or communication standard employed will depend on the specific
application and the overall design constraints imposed on the system.
[0140] Within the present disclosure, the word "exemplary" is used to mean "serving as an
example, instance, or illustration." Any implementation or aspect described herein
as "exemplary" is not necessarily to be construed as preferred or advantageous over
other aspects of the disclosure. Likewise, the term "aspects" does not require that
all aspects of the disclosure include the discussed feature, advantage or mode of
operation. The term "coupled" is used herein to refer to the direct or indirect coupling
between two objects. For example, if object A physically touches object B, and object
B touches object C, then objects A and C may still be considered coupled to one another-even
if they do not directly physically touch each other. For instance, a first object
may be coupled to a second object even though the first object is never directly physically
in contact with the second object. The terms "circuit" and "circuitry" are used broadly,
and intended to include both hardware implementations of electrical devices and conductors
that, when connected and configured, enable the performance of the functions described
in the present disclosure, without limitation as to the type of electronic circuits,
as well as software implementations of information and instructions that, when executed
by a processor, enable the performance of the functions described in the present disclosure.
1. Ein Verfahren, das bei einer Planungseinheit (202) für drahtlose Kommunikation über
einen Zeitduplex-, TDD-, Träger, betreibbar ist, wobei das Verfahren aufweist:
Empfangen (1002) eines ersten Aufwärtsverbindungs-Bursts von einem Benutzer eines
gekoppelten Modus innerhalb eines jeden von einem Abwärtsverbindungs-zentrierten Unterrahmen
und einem Aufwärtsverbindungs-zentrierten Unterrahmen auf dem TDD-Träger,
wobei der Abwärtsverbindungs-zentrierte Unterrahmen ein Unterrahmen ist, bei dem ein
Großteil seiner Zeit für die Kommunikation in Abwärtsverbindungs-Richtung verwendet
wird, und der Aufwärtsverbindungs-zentrierte Unterrahmen ein Unterrahmen ist, bei
dem ein Großteil seiner Zeit für die Kommunikation in Aufwärtsverbindungs-Richtung
verwendet wird, und wobei der gekoppelte Modus ein Modus ist, bei dem ein sondierendes
Referenzsignal, SRS, wiederverwendet wird, um dem Zweck eines Demodulationsreferenzsignals,
DM-RS, zu dienen; und
Empfangen (1004), gleichzeitig mit dem ersten Aufwärtsverbindungs-Burst, eines zweiten
Aufwärtsverbindungs-Bursts von einem Benutzer eines entkoppelten Modus innerhalb jedes
des Abwärtsverbindungs-zentrierten Unterrahmens und des Aufwärtsverbindungs-zentrierten
Unterrahmens auf dem TDD-Träger, wobei der entkoppelte Modus ein Modus ist, in dem
der Benutzer in die Lage versetzt wird, opportunistisch Aufwärtsverbindungs-Nutzlastdaten
mit niedrigen Latenzanforderungen zu übertragen, und
wobei der erste Aufwärtsverbindungs-Burst des Benutzers des gekoppelten Modus mit
dem zweiten Aufwärtsverbindungs-Burst des Benutzers des entkoppelten Modus auf dem
TDD-Träger unter Verwendung von nichtorthogonalem Mehrfachzugriff kombiniert ist.
2. Das Verfahren nach Anspruch 1, weiter aufweisend:
Speichern (1102) des empfangenen ersten Aufwärtsverbindungs-Bursts und des zweiten
Aufwärtsverbindungs-Bursts im Speicher;
Dekodieren (1104) des zweiten Aufwärtsverbindungs-Bursts des Benutzers des entkoppelten
Modus;
Anwenden (1106) einer Interferenzunterdrückung, um den zweiten Aufwärtsverbindungs-Burst
aus den gespeicherten empfangenen Bursts zu entfernen; und
Dekodieren (1108) des ersten Aufwärtsverbindungs-Bursts des Benutzers des gekoppelten
Modus von den Interferenz-unterdrückten empfangenen Aufwärtsverbindungs-Bursts.
3. Das Verfahren nach Anspruch 1, weiter aufweisend:
Übertragen einer Steuernachricht an mindestens einen der Benutzer des entkoppelten
Modus oder den Benutzer des gekoppelten Modus, wobei die Steuernachricht konfiguriert
ist, um einen Beitrag des ersten Aufwärtsverbindungs-Bursts und/oder des zweiten Aufwärtsverbindungs-Bursts
zu einem thermischen Anstieg, RoT, zu steuern, der von der Planungseinheit (202) erfasst
wird.
4. Das Verfahren nach Anspruch 3, wobei die Steuernachricht einen Hinweis auf ein Modulations-
und Kodierungsschema, MCS, aufweist, das vom Benutzer des entkoppelten Modus verwendet
werden soll.
5. Das Verfahren nach Anspruch 3, wobei die Steuernachricht einen Leistungssteuerbefehl
zum Einstellen einer Leistung des zweiten Aufwärtsverbindungs-Bursts vom Benutzer
des entkoppelten Modus aufweist.
6. Das Verfahren nach Anspruch 3, wobei die Steuernachricht einen Leistungssteuerbefehl
zum Einstellen einer Leistung des ersten Aufwärtsverbindungs-Bursts vom Benutzer des
gekoppelten Modus aufweist.
7. Ein Verfahren, das bei einer Planungseinheit (202) für drahtlose Kommunikation über
einen Zeitduplex-, TDD-, Träger, betreibbar ist, wobei das Verfahren aufweist:
Empfangen (1302) eines ersten Aufwärtsverbindungs-Bursts von einem Benutzer eines
gekoppelten Modus innerhalb eines jeden von einem Abwärtsverbindungs-zentrierten Unterrahmen
und einem Aufwärtsverbindungs-zentrierten Unterrahmen auf dem TDD-Träger,
wobei der Abwärtsverbindungs-zentrierte Unterrahmen ein Unterrahmen ist, bei dem ein
Großteil seiner Zeit für die Kommunikation in Abwärtsverbindungs-Richtung verwendet
wird, und der Aufwärtsverbindungs-zentrierte Unterrahmen ein Unterrahmen ist, bei
dem ein Großteil seiner Zeit für die Kommunikation in Aufwärtsverbindungs-Richtung
verwendet wird, und wobei der gekoppelte Modus ein Modus ist, bei dem ein sondierendes
Referenzsignal, SRS,
wiederverwendet wird, um dem Zweck eines Demodulationsreferenzsignals, DM-RS, zu dienen;
und
Empfangen (1304), gleichzeitig mit dem ersten Aufwärtsverbindungs-Burst, eines zweiten
Aufwärtsverbindungs-Bursts von einem Benutzer eines entkoppelten Modus innerhalb jedes
des Abwärtsverbindungs-zentrierten Unterrahmens und des Aufwärtsverbindungs-zentrierten
Unterrahmens auf dem TDD-Träger, wobei der entkoppelte Modus ein Modus ist, in dem
der Benutzer in die Lage versetzt wird, opportunistisch Aufwärtsverbindungs-Nutzlastdaten
mit niedrigen Latenzanforderungen zu übertragen, und
wobei der erste Aufwärtsverbindungs-Burst des Benutzers des gekoppelten Modus mit
dem zweiten Aufwärtsverbindungs-Burst des Benutzers des entkoppelten Modus auf dem
TDD-Träger unter Verwendung von orthogonalem Mehrfachzugriff kombiniert ist.
8. Das Verfahren nach Anspruch 7, wobei der erste Aufwärtsverbindungs-Burst des Benutzers
des gekoppelten Modus mindestens ein Symbol aufweist, das Aufwärtsverbindungs-Steuerinformationen
aufweist, wobei die Aufwärtsverbindungs-Steuerinformationen als eine einzige Trägerwellenform
strukturiert sind, die einen verschachtelten Frequenzmultiplex-Mehrfachzugriff, IFDMA,
verwendet, der eine Teilmenge von Unterträgern über Ressourcenblöcke in dem TDD-Träger
hinweg belegt.
9. Das Verfahren nach Anspruch 8, wobei der zweite Aufwärtsverbindungs-Burst vom Benutzer
des entkoppelten Modus mindestens ein Symbol aufweist, das Aufwärtsverbindungs-Steuerinformationen
aufweist, wobei die Aufwärtsverbindungs-Steuerinformationen als eine orthogonale Frequenzmultiplex-,
OFDM-, Wellenform strukturiert sind, verschachtelt zwischen mindestens einem Teil
der Unterträger, aus denen die Aufwärtsverbindungs-Steuerinformationen bestehen, die
dem ersten Aufwärtsverbindungs-Burst des Benutzers des gekoppelten Modus entsprechen.
10. Eine Planungseinheit (202), die für drahtlose Kommunikation über einen Zeitduplex-,
TDD-, Träger konfiguriert ist, wobei die Planungseinheit (202) aufweist:
Mittel zum Empfangen eines ersten Aufwärtsverbindungs-Bursts von einem Benutzer eines
gekoppelten Modus innerhalb eines jeden von einem Abwärtsverbindungs-zentrierten Unterrahmen
und einem Aufwärtsverbindungs-zentrierten Unterrahmen auf dem TDD-Träger,
wobei der Abwärtsverbindungs-zentrierte Unterrahmen ein Unterrahmen ist, bei dem ein
Großteil seiner Zeit für die Kommunikation in Abwärtsverbindungs-Richtung verwendet
wird, und der Aufwärtsverbindungs-zentrierte Unterrahmen ein Unterrahmen ist, bei
dem ein Großteil seiner Zeit für die Kommunikation in Aufwärtsverbindungs-Richtung
verwendet wird, und wobei der gekoppelte Modus ein Modus ist, bei dem ein sondierendes
Referenzsignal, SRS, wiederverwendet wird, um dem Zweck eines Demodulationsreferenzsignals,
DM-RS, zu dienen; und
Mittel zum Empfangen, gleichzeitig mit dem ersten Aufwärtsverbindungs-Burst, eines
zweiten Aufwärtsverbindungs-Bursts von einem Benutzer eines entkoppelten Modus innerhalb
jedes des Abwärtsverbindungs-zentrierten Unterrahmens und des Aufwärtsverbindungs-zentrierten
Unterrahmens auf dem TDD-Träger, wobei der entkoppelte Modus ein Modus ist, in dem
der Benutzer in die Lage versetzt wird, opportunistisch Aufwärtsverbindungs-Nutzlastdaten
mit niedrigen Latenzanforderungen zu übertragen, und
wobei der erste Aufwärtsverbindungs-Burst des Benutzers des gekoppelten Modus mit
dem zweiten Aufwärtsverbindungs-Burst des Benutzers des entkoppelten Modus auf dem
TDD-Träger unter Verwendung von nichtorthogonalem Mehrfachzugriff kombiniert ist.
11. Die Planungseinheit (202) nach Anspruch 10, weiter aufweisend:
Mittel zum Speichern des empfangenen ersten Aufwärtsverbindungs-Bursts und des zweiten
Aufwärtsverbindungs-Bursts im Speicher;
Mittel zum Dekodieren des zweiten Aufwärtsverbindungs-Bursts des Benutzers des entkoppelten
Modus;
Mittel zum Anwenden einer Interferenzunterdrückung, um den zweiten Aufwärtsverbindungs-Burst
aus den gespeicherten empfangenen Bursts zu entfernen; und
Mittel zum Dekodieren des ersten Aufwärtsverbindungs-Bursts des Benutzers des gekoppelten
Modus von den Interferenz-unterdrückten empfangenen Aufwärtsverbindungs-Bursts.
12. Die Planungseinheit (202) nach Anspruch 10, weiter aufweisend Mittel zum Übertragen
einer Steuernachricht an mindestens einen der Benutzer des entkoppelten Modus oder
den Benutzer des gekoppelten Modus, wobei die Steuernachricht konfiguriert ist, um
einen Beitrag des ersten Aufwärtsverbindungs-Bursts und/oder des zweiten Aufwärtsverbindungs-Bursts
zu einem thermischen Anstieg, RoT, zu steuern, der von der Planungseinheit (202) erfasst
wird.
13. Die Planungseinheit (202) nach Anspruch 12, wobei die Steuernachricht eine Anzeige
eines Modulations- und Kodierungsschemas, MCS, aufweist, das vom Benutzer des entkoppelten
Modus verwendet werden soll.
14. Eine Planungseinheit (202), die für drahtlose Kommunikation über einen Zeitduplex-,
TDD-, Träger konfiguriert ist, wobei die Planungseinheit (202) aufweist:
Mittel zum Empfangen eines ersten Aufwärtsverbindungs-Bursts von einem Benutzer eines
gekoppelten Modus innerhalb eines jeden von einem Abwärtsverbindungs-zentrierten Unterrahmen
und einem Aufwärtsverbindungs-zentrierten Unterrahmen auf dem TDD-Träger,
wobei der Abwärtsverbindungs-zentrierte Unterrahmen ein Unterrahmen ist, bei dem ein
Großteil seiner Zeit für die Kommunikation in Abwärtsverbindungs-Richtung verwendet
wird, und der Aufwärtsverbindungs-zentrierte Unterrahmen ein Unterrahmen ist, bei
dem ein Großteil seiner Zeit für die Kommunikation in Aufwärtsverbindungs-Richtung
verwendet wird, und wobei der gekoppelte Modus ein Modus ist, bei dem ein sondierendes
Referenzsignal, SRS, wiederverwendet wird, um dem Zweck eines Demodulationsreferenzsignals,
DM-RS, zu dienen; und
Mittel zum Empfangen, gleichzeitig mit dem ersten Aufwärtsverbindungs-Burst, eines
zweiten Aufwärtsverbindungs-Bursts von einem Benutzer eines entkoppelten Modus innerhalb
jedes des Abwärtsverbindungs-zentrierten Unterrahmens und des Aufwärtsverbindungs-zentrierten
Unterrahmens auf dem TDD-Träger, wobei der entkoppelte Modus ein Modus ist, in dem
der Benutzer in die Lage versetzt wird, opportunistisch Aufwärtsverbindungs-Nutzlastdaten
mit niedrigen Latenzanforderungen zu übertragen, und
wobei der erste Aufwärtsverbindungs-Burst des Benutzers des gekoppelten Modus mit
dem zweiten Aufwärtsverbindungs-Burst des Benutzers des entkoppelten Modus auf dem
TDD-Träger unter Verwendung von orthogonalem Mehrfachzugriff kombiniert ist.
15. Ein computerlesbares Medium, aufweisend einen Code, um einen Computer zu veranlassen,
die Schritte eines Verfahrens nach einem der Ansprüche 1 bis 6 und 7 bis 9 auszuführen,
wenn der Code von einem Computer ausgeführt wird.